The present invention relates in general to a temperature sensor for sensing the temperature of a gas. More specifically, the invention relates to an integrated sensor that includes a temperature sensor, which has incorporated therein a temperature sensor element for measuring the temperature of a gas, and a pressure sensor element.
FIGS. 6 and 7 illustrate an example of an integrated sensor that includes a pressure sensor integrated with a temperature sensor, which is set up in an intake manifold of a vehicle and measures the temperature and pressure of an intake air/fuel mixture within the intake manifold. FIG. 6 is a vertical cross-sectional view of a central part of an integrated sensor 100. FIG. 7A is a plan view showing the integrated sensor 100 of FIG. 6 installed in a position to measure the pressure within an intake manifold 200 of a vehicle.
As shown in FIG. 6, a cylindrical pressure introducing port 101, configured to be inserted into an opening provided in the intake manifold 200 as shown in FIG. 7B, extends from a main body 111 of the sensor 100. A gasket 99 is provided to seal the opening around the cylindrical pressure introducing port 101 when it is inserted into the manifold 200, thereby preventing gas from escaping from the pressure manifold 200 during engine operation. A pressure inlet 102 is located on a central axis of the pressure introducing port 101. A pressure sensor element 104 mounted on a cell case 103 is disposed on an upper end portion of the pressure introducing port 101, and is connected to a connector pin 107 via a lead terminal 106. The connector pin 107 in turn is connectable to a connector (not shown) that is inserted within a connector socket 108 that is formed integral with the main body 111. A pressure detection chamber 105 communicating with the pressure inlet 102 is formed below the pressure sensor element 104.
The pressure sensor element 104 is constructed by bridge-connecting a plurality of semiconductor strain gauges on a diaphragm composed of single-crystal silicon or the like. When the diaphragm is deformed by a change of gas pressure in the pressure detection chamber 105, the resistance of the semiconductor strain gauges is changed by a piezoelectric effect in accordance with the volume of the deformation. Based on this principle, the gas pressure of the pressure detection chamber 105, which is the gas pressure of the air/fuel mixture within the intake manifold 200, can be detected by detecting a voltage signal equivalent to the gauge resistance ratio.
Furthermore, a temperature sensor element 109 for measuring the temperature within the intake manifold 200 is disposed on a line extending along an axial direction of the pressure introducing port 101, and a lead wire 110 passes through the pressure inlet 102 and connects the temperature sensor element 109 to the connector pin 107. The temperature sensor element 109 is provided in order to detect the temperature within the intake manifold 200, as the pressure to be measured by the pressure sensor element 104 is related to temperature. The temperature sensor element 109 (for example, a thermister) includes a substantially cylindrical sensor body element 109a and a pair of lead terminals 109b that extend from both ends of the substantially cylindrical sensor body element 109a along an axial direction thereof.
The main body 111 is formed so as to surround an upper part of the pressure introducing port 101, and the connector socket 108 is configured to form a part of the exterior case 111 as described above. It should be noted that a mounting hole 112 is provided for fixing the integrated sensor 100 to the intake manifold 200 with a screw, bolt or some other mechanical attachment mechanism.
As stated above, FIG. 7 illustrates the integrated sensor 100 installed on or attached to the intake manifold 200 of a vehicle engine. The sensor body element 109a is disposed such that a central axis (c) of the sensor body element 109a is disposed perpendicular to an air flow direction of the intake manifold 200. As shown in FIGS. 7A and 7B, the position at which the integrated sensor 100 is attached to the intake manifold 200 is called “ideal attachment position” for the purposes of this discussion. In other words, in the integrated sensor 100 having the structure shown in FIG. 6 and FIG. 7, it is necessary to attach the integrated sensor 100 to the intake manifold 200 such that the connector socket 108 with the connector pin 107 becomes parallel to the central axis of the intake manifold 200 in order for the central axis of the main body element 109a to be perpendicular to the direction of air flow.
The above-described ideal mounting position, however, places limitations on vehicle designers as to where and how the integrated sensor 100 is to be positioned and oriented when installed in a vehicle. Accordingly, it would be desirable to provide an integrated sensor that was not limited to the above-described angular range